GHRP-2
Potent GH secretagogue — stronger GH release than Ipamorelin but with cortisol and prolactin co-stimulation.
Research facts
| Half-life | ~3–4h |
|---|---|
| Route | SubQ / IV |
| Typical dose | 100–200 mcg |
| Frequency | 2–3× daily |
| Solvent | Bacteriostatic water |
| pH | 5.5–7.5 |
| Stability | 30 days at +4°C |
Mechanism of action
GHRP-2 is a synthetic hexapeptide ghrelin mimetic that activates the GHS-R1a (growth hormone secretagogue receptor) — the same receptor as Ipamorelin and ghrelin. However, unlike Ipamorelin, GHRP-2 also activates corticotropin (CRH) and prolactin pathways in a dose-dependent manner, leading to meaningful cortisol and prolactin elevation at effective doses. It produces the highest GH peak of the GHRP class. It is FDA-approved (as Pralmorelin) for diagnostic testing of GH deficiency — where its potent GH stimulation is the desired endpoint. Clinical diagnostic use at 1 mcg/kg has well-established pharmacodynamic data.
Documented effects (research-model)
- Highest GH pulse amplitude among GHRPs
- FDA-approved diagnostic for GH deficiency testing (Pralmorelin)
- Appetite stimulation via ghrelin receptor
- Strong IGF-1 elevation
Research protocols
| Protocol | Dose | Frequency | Cycle | Vial |
|---|---|---|---|---|
| Standard | 100 mcg SubQ | 2× daily (AM fasted + bedtime) | 8–12 weeks | 5mg / 5mL BAC water |
Research context only. Not medical advice. Consult a qualified healthcare professional before any protocol decision.
Synergies
- CJC-1295 HIGH
GHRH + GHRP synergy. GHRP-2 provides the strongest GH pulse of the GHRP class when combined with CJC-1295, but cortisol co-stimulation is a drawback.
Myths & misconceptions
Evidence gaps
- Direct comparison to Ipamorelin for body composition outcomes in RCTs.
- Long-term HPA axis effects with chronic GHRP-2 use.
Safety notes
Cortisol and prolactin elevation at effective doses. Monitor cortisol, prolactin, and IGF-1. More side effects than Ipamorelin at equivalent GH-stimulatory doses. Not preferred over Ipamorelin for research use.
Biomarkers to monitor
Primary-source citations
- PMID 9849822 — GHRP-2 versus Ipamorelin — comparative selectivity analysis (Eur J Endocrinol. 1999)
Frequently asked
What is GHRP-2?
GHRP-2 (Growth Hormone Releasing Peptide-2 — Pralmorelin) is a research compound classified in our library as Tier C — Limited human trials; effect size uncertain.. Potent GH secretagogue — stronger GH release than Ipamorelin but with cortisol and prolactin co-stimulation.
What is the evidence tier for GHRP-2?
We classify GHRP-2 as Tier C: Limited human trials; effect size uncertain. See our full peptide evidence tiers explainer for how we assign S/A/B/C/D.
What is the research dose of GHRP-2?
For GHRP-2, typical research dose is 100–200 mcg, route is SubQ / IV, half-life is ~3–4h. Protocols vary by research goal — see the protocols section on this page for standard and advanced dosing schedules. Research use only, not medical advice.
What does GHRP-2 stack well with?
GHRP-2 stacks well with CJC-1295. GHRH + GHRP synergy. GHRP-2 provides the strongest GH pulse of the GHRP class when combined with CJC-1295, but cortisol co-stimulation is a drawback.
Is GHRP-2 safe?
Cortisol and prolactin elevation at effective doses. Monitor cortisol, prolactin, and IGF-1. Research context only — no compound on this site is approved for human therapeutic use unless explicitly noted.